Bug #19745: Confirm correct behaviour when attaching private method with `#define_singleton_method`

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: HEAD
• Backport: 3.0: UNKNOWN, 3.1: UNKNOWN, 3.2: UNKNOWN

[itarato (Peter Arato)]

Should dynamically added private methods be accessible publicly?

See the following example?

private def bar; end

foo = Object.new
foo.define_singleton_method(:bar, method(:bar))

foo.bar # No error.

The script above runs fine on latest Ruby HEAD. Is this correct to ignore the fact that the added method (method(:bar)) is private?

This came up during a TruffleRuby investigation (https://github.com/oracle/truffleruby/issues/3134) where the result for the same script is: private method 'bar' called for #<Object:0xc8> (NoMethodError)

[jeremyevans0 (Jeremy Evans)]

• Status changed from Open to Closed

It is expected that define_singleton_method defines a public singleton method (see #18561). For define_method, visibility can depend on the current default visibility for the class/module scope. In any case, the visibility of the defined method does not depend on the method body (second argument/block). So this would be a bug in TruffleRuby.

[Eregon (Benoit Daloze)]

@itarato (Peter Arato) This example is not the same as the linked issue.
I would suggest to open a separate issue to dicuss the original example, which uses define_method.

(although this define_singleton_method example does fail on TruffleRuby, we should fix define_singleton_method)

[itarato (Peter Arato)]

• Subject changed from Confirm correct behaviour when attaching private method with `#define_method`/`#define_singleton_method` to Confirm correct behaviour when attaching private method with `#define_singleton_method`